Oral bacteria directly affect the disease status of dental caries and periodontal diseases. The dynamic oral microbiota cooperates with the host to reflect the information and status of immunity and metabolism through two-way communication along the oral cavity and the systemic organs. The oral cavity is one of the most important interaction windows between the human body and the environment. The microenvironment at different sites in the oral cavity has different microbial compositions and is regulated by complex signaling, hosts, and external environmental factors. These processes may affect or reflect human health because certain health states seem to be related to the composition of oral bacteria, and the destruction of the microbial community is related to systemic diseases. In this review, we discussed emerging and exciting evidence of complex and important connections between the oral microbes and multiple human systemic diseases, and the possible contribution of the oral microorganisms to systemic diseases. This review aims to enhance the interest to oral microbes on the whole human body, and also improve clinician's understanding of the role of oral microbes in systemic diseases. Microbial research in dentistry potentially enhances our knowledge of the pathogenic mechanisms of oral diseases, and at the same time, continuous advances in this frontier field may lead to a tangible impact on human health.
Bacteria ; Dental Caries/microbiology* ; Humans ; Microbiota ; Mouth/microbiology* ; Mouth Diseases/microbiology* ; Periodontal Diseases/microbiology*

A human oral microbiota is the ecological community of commensal, symbiotic, and pathogenic microorganisms found in human oral cavity. Oral microbiota exists mostly in the form of a biofilm and maintains a dynamic ecological equilibrium with the host body. However, the disturbance of this ecological balance inevitably causes oral infectious diseases, such as dental caries, apical periodontitis, periodontal diseases, pericoronitis, and craniofacial bone osteomyelitis. Oral microbiota is also correlated with many systemic diseases, including cancer, diabetes mellitus, rheumatoid arthritis, cardiovascular diseases, and preterm birth. Hence, oral microbiota has been considered as a potential biomarker of human diseases. The "Human Microbiome Project" and other metagenomic projects worldwide have advanced our knowledge of the human oral microbiota. The integration of these metadata has been the frontier of oral microbiology to improve clinical translation. By reviewing recent progress on studies involving oral microbiota-related oral and systemic diseases, we aimed to propose the essential role of oral microbiota in the prediction of the onset, progression, and prognosis of oral and systemic diseases. An oral microbiota-based prediction model helps develop a new paradigm of personalized medicine and benefits the human health in the post-metagenomics era.
Biomarkers ; Cardiovascular Diseases ; microbiology ; Dental Caries ; microbiology ; Diabetes Mellitus ; microbiology ; Humans ; Metagenomics ; Microbiota ; Mouth ; microbiology ; Mouth Diseases ; microbiology ; Neoplasms ; microbiology ; Oral Health ; Periodontal Diseases ; microbiology

Humans ; Periodontal Diseases ; complications ; microbiology ; Periodontium ; microbiology ; Systemic Inflammatory Response Syndrome ; microbiology

OBJECTIVETo study dynamic relation between periodontal pathogens and cariogenic bacteria under analogous oral environment.

METHODSEight periodontopathic and cariogenic bacteria of Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn), Provotella intermedium (Pi), Streptococcus mutans (Sm), Streptococcus sanguis (Ss), Actinomyces viscosus (Av) and Lactobacillus acidophilus (La) were used. These eight strains were cultured in modified chemostat under analogous oral environment which contained 600 ml modified BM medium supplemented with 2.5 g/L porcine gastric mucin, respectively. After 1, 24, 48 and 96 h, optical sectioning of plaque biofilms on removable and replaceable hydroxyapatite disks was analyzed by the combination of live bacterial Gram fluorescence staining and confocal laser scanning microscopy. Biofilm thickness and reconstruction of the three-dimensional architecture of plaque biofilms were made.

RESULTSBiofilm thickness increased significantly with time (P < 0.001). Biofilms of Aa were thinner than those of Ss and eight-specie biofilms were thicker than those formed by Ss and Aa per time point. Three-dimensional images showed periodontal pathogens mainly occurred in cariogenic bacterial complex or on the biofilm surface.

CONCLUSIONSGram-positive cariogenic species initially predominated in artificial plaque, followed by the increasing proportions of Gram-negative periodontal pathogens. The relation between microecological balance among bacteria and diseases is worthy of further studies.

Bacteria ; growth & development ; Biofilms ; Dental Caries ; microbiology ; Ecology ; Humans ; Microscopy, Confocal ; Periodontal Diseases ; microbiology

Since the initial observations of oral bacteria within dental plaque by van Leeuwenhoek using his primitive microscopes in 1680, an event that is generally recognized as the advent of oral microbiological investigation, oral microbiology has gone through phases of "reductionism" and "holism". From the small beginnings of the Miller and Black period, in which microbiologists followed Koch's postulates, took the reductionist approach to try to study the complex oral microbial community by analyzing individual species; to the modern era when oral researchers embrace "holism" or "system thinking", adopt new concepts such as interspecies interaction, microbial community, biofilms, poly-microbial diseases, oral microbiological knowledge has burgeoned and our ability to identify the resident organisms in dental plaque and decipher the interactions between key components has rapidly increased, such knowledge has greatly changed our view of the oral microbial flora, provided invaluable insight into the etiology of dental and periodontal diseases, opened the door to new approaches and techniques for developing new therapeutic and preventive tools for combating oral polymicrobial diseases.
Bacteria ; classification ; Bacterial Infections ; prevention & control ; Bacterial Physiological Phenomena ; Biofilms ; Dental Plaque ; microbiology ; Humans ; Mouth ; microbiology ; Periodontal Diseases ; microbiology ; prevention & control ; Tooth Diseases ; microbiology ; prevention & control

OBJECTIVETo make qualitative and quantitative analysis of Archaea in subgingival plaque sample and to investigate the relationship between periodontal disease and Archaea.

METHODSSubgingival plaque was collected from 23 patients with aggressive periodontitis, 29 with chronic periodontitis, 35 with plaque-induced gingivitis and 38 healthy controls. Qualitative and quantitative analysis of methanogenic archaea was performed by amplification of the 16S rRNA genes in the DNA extracted from the plaque samples.

RESULTSArchaea were found in 65% of aggressive periodontitis patients, 72% of chronic periodontitis, 26% of gingivitis and zero of healthy subjects. Quantitative analysis showed the average abundance of archaeal 16S rRNA gene in Archaea-positive patients was different among the three groups. The average 16S rRNA gene copy number from per microg wet plaque was 6.66 x 10(6) in aggressive periodontitis sufferers, 4.47 x 10(6) in chronic periodontitis and 1.78 x 10(6) in gingivitis groups. The prevalence of Archaea and the average Archaea 16S rRNA gene numbers in periodontitis groups were higher than those in gingivitis group (P < 0.05).

CONCLUSIONSThis suggests that Archaea may be implicated as causative agents for periodontitis.

Aggressive Periodontitis ; microbiology ; Archaea ; classification ; genetics ; isolation & purification ; Case-Control Studies ; Chronic Periodontitis ; microbiology ; DNA, Bacterial ; genetics ; Dental Plaque ; microbiology ; Humans ; Periodontal Diseases ; microbiology ; RNA, Ribosomal, 16S ; genetics

Aggregatibacter actinomycetemcomitans ; physiology ; Bacterial Adhesion ; Biofilms ; Periodontal Diseases ; microbiology ; Porphyromonas endodontalis ; physiology

OBJECTIVETo investigate the microbiological changes of subgingival microbials in patients with gingivitis and wearing fixed orthodontic appliances.

METHODS48 subjects (10 to 17 years old) with gingivitis, and wearing fixed orthodontic appliances, were divided randomly into three groups (placebo, NS and CH). Placebo group had normal saline mouthrinse; only and no oral hygiene instruction (OHI). The NS group had OHI and normal saline mouthrinse; The CH group had OHI and 0.12% chlorhexidine gluconate mouthrinse. Bacterial examinations were carried out on baseline, one week, one month and three months after scaling. The bacterial examination was carried out. The percentage of coccus, bacillus and spirochete was calculated.

RESULTSIn placebo group and NS group, the percentage of coccus increased up to the third examination then dropped down. The spirochete's percentage changed inversely. CH group maintained an increasing trend in coccus' percentage and decreasing trend in spirochete's percentage. The percentage changes of coccus and bacillus between placebo group and CH group are statistically significant (P < 0.05).

CONCLUSIONSDuring the three-month examination, the CH group had better microbiologic change than the other two groups.

Adolescent ; Child ; Chlorhexidine ; administration & dosage ; analogs & derivatives ; Female ; Gingivitis ; microbiology ; prevention & control ; Humans ; Male ; Malocclusion ; microbiology ; therapy ; Mouthwashes ; Orthodontic Appliances ; Orthodontics, Corrective ; adverse effects ; methods ; Periodontal Attachment Loss ; microbiology ; prevention & control ; Periodontal Diseases ; microbiology ; prevention & control ; Periodontal Pocket ; microbiology ; pathology ; Spirochaetales ; isolation & purification ; Spirochaetales Infections ; microbiology

Halitosis ; etiology ; metabolism ; microbiology ; Helicobacter Infections ; complications ; Helicobacter pylori ; Humans ; Oral Hygiene ; Periodontal Diseases ; complications ; Smoking ; Volatile Organic Compounds ; metabolism

Periodontitis is an inflammatory disease involving the destruction of both soft and hard tissue in the periodontal region. Although dysbiosis of the local microbial community initiates local inflammation, over-activation of the host immune response directly activates osteoclastic activity and alveolar bone loss. Many studies have reported on the cytokine network involved in periodontitis and its crucial and pleiotropic effect on the recruitment of specific immunocytes, control of pathobionts and induction or suppression of osteoclastic activity. Nonetheless, particularities in the stimulation of pathogens in the oral cavity that lead to the specific and complex periodontal cytokine network are far from clarified. Thus, in this review, we begin with an up-to-date aetiological hypothesis of periodontal disease and summarize the roles of cytokines in the host immune response. In addition, we also summarize the latest cytokine-related therapeutic measures for periodontal disease.
Alveolar Bone Loss ; etiology ; Cytokines ; metabolism ; physiology ; Humans ; Inflammation ; Periodontal Diseases ; Periodontitis ; immunology ; microbiology ; Tumor Necrosis Factor-alpha ; physiology